Encapsulated phase change porous layer

ABSTRACT

A cooling device including an encapsulated phase change porous layer that exhibits an increased heat capacity is disclosed. The encapsulated phase change porous layer may include a sintered porous layer, a phase change material formed over the sintered porous layer, and an encapsulation material formed over the phase change material. The encapsulation material may encapsulate the phase change material between the encapsulation material and the sintered porous layer and retain the phase change material between the encapsulation material and the sintered porous layer when a fluid is flowed through or in contact with the encapsulated phase change porous layer.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of and claims priority to U.S.patent application Ser. No. 16/243,625, filed Jan. 9, 2019 and entitled“ENCAPSULATED PHASE CHANGE POROUS LAYER,” which is incorporated byreference herein in its entirety.

BACKGROUND

The present disclosure generally relates to systems and/or methods forincreasing the heat capacity of a highly porous layer.

A cooling device may be coupled to a heat generation device to removeheat from the heat generation device in efforts to minimize damage tothe heat generation device, to increase functional efficiencies of theheat generation device, and/or the like. Some cooling devices utilize acooling fluid to absorb heat from a heat-generating device.

A cooling device may include a porous layer to cool a heat generationdevice. However, due to its network of pores or voids, a porous layermay have a reduced heat capacity. This reduced heat capacity may causethe porous layer to become undesirably hot when the heat generationdevice operates at a high temperature. Accordingly, a porous layerhaving an increased heat capacity that is capable of dissipating heatwhen a heat generation device operates at a high temperature may bedesired. A porous layer that is capable of reducing the operatingtemperature of a heat generation device to an acceptable operatingtemperature may also be desired.

SUMMARY

In one embodiment, a method of forming an encapsulated phase changeporous layer is disclosed. The method may include providing or forming asintered porous layer, forming a phase change material over the sinteredporous layer, and forming an encapsulation material over the phasechange material. The encapsulation material may encapsulate the phasechange material between the encapsulation material and the sinteredporous layer and retain the phase change material between theencapsulation material and the sintered porous layer when a fluid isflowed through or in contact with the encapsulated phase change porouslayer. The encapsulated phase change porous layer may be part of acooling device coupled to a heat generating device to transfer heat awayfrom the heat generation device.

In another embodiment, a cooling device is disclosed. The cooling devicemay include an encapsulated phase change porous layer having a sinteredporous layer, a phase change material formed over the sintered porouslayer, and an encapsulation material formed over the phase changematerial. The encapsulation material may encapsulate the phase changematerial between the encapsulation material and the sintered porouslayer and retain the phase change material between the encapsulationmaterial and the sintered porous layer when a fluid is flowed through orin contact with the encapsulated phase change porous layer. The coolingdevice may be coupled to a heat generation device to transfer heat awayfrom the heat generation device.

In yet another embodiment, a system including a heat generation deviceand a cooling device coupled to the heat generation device is disclosed.The cooling device may include an encapsulated phase change porous layerhaving a sintered porous layer, a phase change material formed over thesintered porous layer, and an encapsulation material formed over thephase change material. The encapsulation material may encapsulate thephase change material between the encapsulation material and thesintered porous layer and retain the phase change material between theencapsulation material and the sintered porous layer when a fluid isflowed through or in contact with the encapsulated phase change porouslayer. The cooling device may transfer heat away from the heatgeneration device of the system.

These and additional features provided by the embodiments describedherein will be more fully understood in view of the following detaileddescription, in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments set forth in the drawings are illustrative and exemplaryin nature and not intended to limit the subject matter defined by theclaims. The following detailed description of the illustrativeembodiments can be understood when read in conjunction with thefollowing drawings, wherein like structure is indicated with likereference numerals and in which:

FIG. 1A depicts a simple block diagram of an illustrative heat transfersystem, including a cooling device coupled to a heat generation device,according to one or more embodiments shown and described herein.

FIG. 1B depicts an illustrative porous layer according to one or moreembodiments shown and described herein.

FIG. 2A schematically depicts a perspective view of an opal structureutilized to form a porous layer according to one or more embodimentsshown and described herein.

FIG. 2B schematically depicts a material deposited over the opalstructure of FIG. 2A according to one or more embodiments shown anddescribed herein.

FIG. 2C schematically depicts the material of FIG. 2B after the opalstructure of FIG. 2A is removed, thereby forming a porous layeraccording to one or more embodiments shown and described herein.

FIG. 3 depicts an illustration of a cross-section of an encapsulatedphase change porous layer according to one or more embodiments shown anddescribed herein.

FIG. 4 depicts a flow diagram of an illustrative method of forming anencapsulated phase change porous layer according to one or moreembodiments shown and described herein.

DETAILED DESCRIPTION

The present disclosure relates to a porous layer, a method of producingthe porous layer, and systems including the porous layer. According tovarious embodiments disclosed herein, the porous layer may include anencapsulated phase change material against a metal of the porous layer.According to various aspects, the embedded and encapsulated phase changematerial increases the heat capacity of the porous layer.

FIG. 1A depicts a simple block diagram of an illustrative heat transfersystem 100 according to various embodiments described herein. Inreference to FIG. 1A, the heat transfer system 100 may include a coolingdevice 102 coupled to (e.g., positioned in contact with) a heatgeneration device 104. The heat generation device 104 of FIG. 1A is notlimited by the present disclosure and may be generally any device thatgenerates heat as a byproduct of operation. In some embodiments, theheat generation device may be a semiconductor device such as, forexample, an insulated-gate bipolar transistor (IGBT), a diode, atransistor, an integrated circuit, a silicon-controlled rectifier (SCR),a thyristor, a gate turn-off thyristor (GTO), a triac, a bipolarjunction transistor (BJT), a power metal oxide semiconductorfield-effect transistor (MOSFET), a MOS-controlled thyristor (MCT), anintegrated gate-commutated thyristor (IGCT), and/or the like. Otherexamples of a heat generation device, not specifically described herein,should generally be understood, and are included within the scope of thepresent disclosure. The cooling device 102 of FIG. 1A may generally beany device or system that cools via heat transfer. Illustrative examplesof devices or systems that cool via heat transfer (e.g., via heatexchange) include, but are not limited to, pool boiling units, heat pipeassemblies, heat spreaders, vapor chambers, thermoelectric coolingdevices, thermal diodes, and other heat exchange devices notspecifically described herein. Such devices and systems may generallyincorporate and/or may be fluidly coupled to a supply tube 106 thatdirects a cooling fluid into the cooling device 102 and an extract tube108 that removes heated cooling fluid from the cooling device 102. Thesupply tube 106 and the extract tube 108 may be fluidly coupled to oneor more additional components (not shown) for the purposes of directingand/or recirculating the cooling fluid therethrough.

According to various embodiments described herein, the cooling device102 of FIG. 1A may include a porous layer 103 as specifically describedherein. Such a cooling device 102 may be an active heat managementdevice according to some embodiments. That is, the cooling device 102may actively draw heat from the heat generation device 104 as a coolingfluid is flowed through the porous layer 103. However, the coolingdevice 102 may be a passive heat management device in other embodiments.That is, the porous layer 103 itself may act as a device particularlyconfigured to dissipate heat generated by the heat generation device 104by providing an increased surface area for heat dissipation. As activeand passive heat management devices are generally understood, suchdetails are not described further herein.

FIG. 1B illustrates an example porous layer 103′ formed via a sinteringprocess. In view of FIG. 1B, the porous layer 103′ may include amaterial 112 (e.g., a porous layer material) that defines a network ofvoids or pores (e.g., referenced generally as 114). According to variousaspects, the material 112 that defines the network of voids or pores 114may include a metal such as Copper (Cu), Nickel (Ni), and/or the like.According to various embodiments described herein, the network of voidsor pores 114 provide an increased surface area for nucleation of acooling liquid from a liquid to a gas (e.g., passive heat management).The network of voids or pores 114 also provide a structure through whicha cooling fluid (e.g., liquid and/or gas) may flow to cool the porouslayer and the heat generation device coupled thereto (e.g., active heatmanagement).

As introduced, according to various aspects described herein, the porouslayer 103′ of FIG. 1B may be formed via a sintering process by whichmaterial 112 particles or powders (e.g., metals such as Cu, Ni, and/orthe like) are sintered at a predefined sintering temperature for apredefined time period to form the porous layer 103′ with the network ofvoids or pores 114. Various sintering processes should generally beunderstood and are included within the scope of the present disclosure.In view of FIG. 1B, the porous layer 103′ may define voids or pores 114of varying size, varying shape, varying density, and/or varyingdistribution. Accordingly, the material 112 (e.g., metal) of the porouslayer 103′ may include varying cross-sectional shapes and/orthicknesses. According to other aspects, the porous layer 103′ of FIG.1B may be formed by other than a sintering process.

Another example porous layer 103″ may be formed via a metal inverse opal(MIO) process (e.g., a copper inverse opal process (CIO), a nickelinverse opal (NIO) process, and/or the like). FIGS. 2A-2C illustratevarious stages during the formation of the porous layer 103″ via a MIOprocess. FIG. 2C illustrates a resulting porous layer 103″ (e.g., MIOstructure) formed via the MIO process. The porous layer 103″ may have aplurality of dimples 202 (or other similar depression or indentation)and a plurality of pores 204 (e.g., a network of pores 204) such thatcooling fluid present within the porous layer 103″ can flow through eachof the plurality of pores 204 and contact a greater amount of surfacearea for the purposes of heat transfer to the cooling fluid. It shouldbe understood that inverse opal structures (including MIO structures)have a high permeability as inverse opal wick structures provide theadvantage of improved control over pore sizes and distribution. Thenumber of dimples 202, pores 204, and/or other surface features presentin the porous layer 103″ is not limited by the present disclosure, andmay be any number so long as the connectivity between the material 206(e.g., porous layer material, a thermally conductive material) of theporous layer 103″ and a surface or interface of the heat generationdevice (see FIG. 1A, e.g., surface 109 of heat generation device 104) ismaintained. Thus, as fluid flows through the dimples 202, the pores 204,and/or other surface features of the porous layer 103″, latent heat iscarried away from the material 206 of the porous layer 103″ and drawsheat away from the coupled heat generation device (see FIG. 1A, heatgeneration device 104). As particularly shown in FIG. 2C, each of thedimples 202 of the porous layer 103″ may have at least two pores 204therein to maximize fluid flow through each of the dimples 202.

While the dimples 202 depicted in FIG. 2C appear generally spherical inshape, this is merely illustrative. That is, the dimples 202 may be anyshape (including irregular shapes). The shape of the dimples 202 may bedetermined from the shape of the materials used to form the porous layer103″, as described in greater detail herein.

A thickness t of the porous layer 103, 103′, 103″ is not limited by thepresent disclosure, and may generally be any thickness. In someembodiments, the thickness t of the porous layer 103, 103′, 103″ may besuch that a space is maintained within the hollow interior of a coolingdevice structure (see e.g., FIG. 1A, structure 107 of cooling device 102is not entirely filled). In other embodiments, the thickness t of theporous layer 103, 103′, 103″ may be such that the porous layer 103,103′, 103″ fills an entire hollow interior of the cooling devicestructure (not shown, e.g., structure 107 of cooling device 102 entirelyfilled).

The porous layer 103″ of FIG. 2C may generally be constructed of amaterial 206 (e.g., a thermally conductive material or the like), but isotherwise not limited by the present disclosure. In some embodiments,the material 206 used for the porous layer 103″ may be selected based onthe process used to form the porous layer 103″, as described in greaterdetail herein. For example, if the porous layer 103″ is formed via anMIO formation process, metals that are suitable for such a formationprocess may be used. Illustrative examples of materials that may be usedinclude, but are not limited to, aluminum, nickel, copper, silver, gold,an alloy containing any of the foregoing, a compound containing any ofthe foregoing, and the like. Other materials that are generallyunderstood to result from an inverse opal formation process that are notspecifically disclosed herein are also included within the scope of thepresent disclosure.

The various stages, illustrated in FIGS. 2A-2C, during formation of theporous layer 103″ including an inverse opal structure (e.g., MIO) is nowdescribed. It should be understood that other processes to achieve theporous layer 103″ may also be used without departing from the scope ofthe present disclosure.

Referring to FIG. 2A, an opal structure 208 may be positioned within acooling device 210 (see FIG. 1A, e.g., similar to the hollow interior ofcooling device 102). More particularly, the opal structure 208 may bepositioned on an interior surface 212 of the cooling device 210 in alocation where a porous layer 103″ is desired (see FIG. 1A, e.g.,surface 105 of cooling device 102 that will interface with surface 109of heat generation device 104). According to alternative embodiments,the opal structure may be positioned on and formed (as described herein)directly on the surface 109 of the heat generation device 104. In lightof FIG. 2A, the opal structure 208 may generally be a lattice ofmaterial (e.g., a mesh) that is shaped, sized, and configured to formthe dimples 202, pores 204, and/or other surface features of the porouslayer 103″ in the negative space that remains after removal of the opalstructure 208, as described herein. Accordingly, the opal structure 208may generally be constructed of a material 214 that can later bedissolved, etched, or otherwise removed without altering the shape ofthe dimples 202, pores 204, and/or other surface features, as describedherein. In some embodiments, the opal structure 208 may be a polymermaterial, such as, for example, a polystyrene opal structure. In someembodiments, the opal structure 208 may be provided as a film, such as apolystyrene opal film. In other embodiments, the opal structure 208 maybe a self-assembled opal structure.

Several methods of constructing the opal structure 208 are possible. Oneillustrative method to synthesize the opal structure 208 is via acontrolled withdrawal process whereby a colloidal suspension of spheresis provided within the cooling device 210, a substrate is inserted intothe suspension in order to create a meniscus line within the coolingdevice 210, and the suspending agent (e.g., water) is slowly evaporated.In such an aspect, the surface tension of the evaporating suspendingagent at the top of the meniscus line pulls the spheres into a closelypacked array no more than a few layers thick, leaving the opal structure208 of spheres within the cooling device 210. This opal structure 208 ofspheres, as depicted in FIG. 2A, is arranged such that plurality ofvoids 216 are present around each of the spheres of the opal structure208. The voids 216 receive material 206 that is used to form the porouslayer (FIG. 2C), as described hereinbelow.

Referring now to FIG. 2B, material 206 may be deposited over the opalstructure 208 and the interior surface 212 of the cooling device 210.The material 206 may generally be deposited such that the material 206fills the voids 216 (FIG. 2A) around the spheres of the opal structure208. The material 206 that is deposited is generally the material 206that results in the porous layer 103″ described herein. That is, thematerial 206 may be aluminum, nickel, copper, silver, gold, an alloycontaining any of the foregoing, a compound containing any of theforegoing, and the like. Additional materials may also be used withoutdeparting from the scope of the present disclosure.

Still referring to FIG. 2B, the material 206 may be deposited via anygenerally recognized method of deposition, such as, for example,chemical vapor deposition (CVD), electrodeposition, epitaxy, and thermaloxidation. In some embodiments, physical vapor deposition (PVD) orcasting may also be used to deposit the material 206. It should beunderstood that the deposition process may or does not completely fillthe interstitial spaces (e.g., the voids 216), but rather creates alayer of material around the spheres such that, when the spheres areremoved, the dimples 202, pores 204, and/or other surface features ofthe porous layer 103″ are formed.

Referring to FIGS. 2B-2C, the opal structure 208 may be removed suchthat the material 206 formed around the opal structure 208 remains asthe porous layer 103″ having the dimples 202, pores 204, and/or othersurface features. More particularly, removal of the spheres of the opalstructure 208 defines the dimples 202 and locations where the sphereswere in contact define the pores 204. Removal of the opal structure 208may generally be completed via any removal processes, particularlyremoval processes that are suitable for removing the material 214 usedfor the opal structure 208 (e.g., polystyrene material) but not thematerial 206 that defines the porous layer 103″. For example, an etchingprocess may be used to remove the material 214 of the opal structure208. That is, an etchant may be applied to the opal structure 208 andthe material 206 (e.g., by placing the opal structure 208 and thematerial 206 in an etchant bath) to etch away the material 214 opalstructure 208. In some embodiments, a hydrofluoric acid solution may beused as an etchant to etch away the opal structure 208. Other methodsthat cause the opal structure 208 to be removed or otherwise dissolvedshould generally be understood. As a result of this process, the porouslayer 103″ (FIG. 2C) is formed on the interior surface 212 of thecooling device 210.

Within this backdrop, regardless of the process through which the porouslayer 103, 103′, 103″ has been formed (e.g., a sintering process, a MIOprocess, and/or the like), FIG. 3 illustrates a cross-section of anencapsulated phase change porous layer 300 formed, as described herein(see FIG. 4), using a porous layer (e.g., 103, 103′, 103″). According tovarious embodiments, the porous layer 103, as depicted in FIG. 1A, maybe substituted with the encapsulated phase change porous layer 300formed as described herein (see FIG. 4).

FIG. 3, according to various aspects, depicts a cross-section of metal301 including a metal surface 302 as defined by a porous layer (e.g.,porous layer 103′ of FIG. 1B, porous layer 103″ of FIG. 2C, and/or thelike). For example, the cross section of metal 301 depicted in FIG. 3may be a cross-section of the material 112 (e.g., metal) specificallyreferenced in FIG. 1B or a cross-section of the material 206 (e.g.,metal) specifically reference in FIG. 2C.

As illustrated in FIG. 3, according to various aspects, the variouscomponents (e.g., metal 301, phase change material 304, encapsulationmaterial 308) may have a circular cross-section. According to otheraspects, the various components (e.g., metal 301, phase change material304, encapsulation material 308) may have a cross-section other than acircular cross-section (e.g., a square cross-section, a variablecross-section). The cross-section of the various components is notlimited in the present disclosure.

As previously highlighted, the metal surface 302 of the overall porouslayer (e.g. porous layer 103′ of FIG. 1B, porous layer 103″ of FIG. 2C,and/or the like), if utilized alone, may exhibit a limited or reducedheat capacity for dissipating heat from a heat generation device coupledthereto. As such, according to embodiments described herein, anencapsulated phase change porous layer 300 including a phase changematerial 304 and an encapsulation material 308 is disclosed. Inparticular, to form the encapsulated phase change porous layer 300, aphase change material 304 may be formed (e.g., coated, layered,deposited, and/or the like) on the metal surface 302. The phase changematerial 304 may be formed on the metal surface 302 via any depositionmethod now known or later developed, particularly deposition methodsthat are suited for the materials used. In some embodiments, the phasechange material 304 may be deposited on the metal surface 302 via atomiclayer deposition (ALD), chemical vapor deposition (CVD) processes,and/or the like.

According to various aspects, the phase change material 304 may includetin (Sn), indium (In), paraffin wax (e.g., C_(n)H_(2n+2)) and/or thelike. In view of FIG. 3, the phase change material 304 may be formed onthe metal surface 302 (e.g., exposed surfaces) to a thickness 306 (e.g.,a phase change material thickness, a first thickness, a predeterminedthickness and/or the like). According to various aspects, the thickness306 of the phase change material 304 may be uniform or non-uniform.According to some aspects the thickness 306 of the phase change materialmay be a function of the thermal energy that the encapsulated phasechange porous layer 300 is anticipated or intended to store. Accordingto further aspects, the phase change material 304 may not cover theentire metal surface 302 (e.g., the phase change material 304 may covera partial portion of the circumference of the metal surface 302 if themetal surface 302 has a circular cross-section, the phase changematerial 304 may cover a partial portion of the metal surface 302 if themetal surface 302 does not have a circular cross-section, and/or thelike).

As illustrated in FIG. 3, an encapsulation material 308 may be formed(e.g., coated, layered, deposited, and/or the like) on the phase changematerial 304 to encapsulate the phase change material 304 between theencapsulation material 308 and the metal surface 302. The encapsulationmaterial 308 may be formed on the phase change material 304 via anydeposition method now known or later developed, particularly depositionmethods that are suited for the materials used. In some embodiments, theencapsulation material 308 may be deposited on the phase change materialvia atomic layer deposition (ALD), chemical vapor deposition (CVD)processes, and/or the like.

According to various aspects, the encapsulation material 308 may includeplatinum (Pt), copper (Cu), aluminum (Al) and/or the like. In view ofFIG. 3, the encapsulation material 308 may be formed on the phase changematerial 304 to a thickness 310 (e.g., an encapsulation materialthickness, a second thickness, a predetermined thickness, and/or thelike). According to various aspects the thickness of the encapsulationmaterial may be uniform or non-uniform. According to some aspects, thethickness 310 of the encapsulation material 308 may be a function of thethermal expansion of the phase change material 304 during storage of thethermal energy anticipated or intended to be stored by the encapsulatedphase change porous layer 300. According to further aspects, theencapsulation material 308 may not surround or encapsulate the entiremetal surface 302. For example, if the phase change material 304 coversonly a partial portion of the metal surface 302, as described herein,the encapsulation material 308 may only surround or encapsulate thephase change material 304 that covers the partial portion of the metalsurface 302 (e.g., thereby encapsulating the phase change material 304between the encapsulation material 308 and the metal surface 302).According to alternative aspects, the encapsulation material 308 maysurround the entire metal surface 302 regardless of whether the phasechange material 304 covers a partial portion of the metal surface 302(e.g., the encapsulation material 308 may not only encapsulate the phasechange material 304 between the encapsulation material 308 and the metalsurface 302 but also encapsulate a portion of the metal surface notcovered by the phase change material).

Viewing FIG. 3 in light of FIGS. 1B and 2C, a combined thickness (e.g.,thickness 306 of the phase change material 304 and thickness 310 of theencapsulation material 308) may further be a function of the size,shape, density and/or distribution of the network of voids or pores (seeFIG. 1B—pores 114, FIG. 2C—dimples 202 and pores 204, and/or the like)of the porous layer (e.g. porous layer 103′ of FIG. 1B, porous layer103″ of FIG. 2C, and/or the like). According to various aspects, thecombined thickness (e.g., thickness 306 of the phase change material 304and thickness 310 of the encapsulation material 308) would notsubstantially inhibit the fluid communication of a cooling fluid (e.g.,liquid and/or gas) through the encapsulated phase change porous layer300 and/or substantially plug or eliminate sites for the nucleation of acooling liquid (e.g., from a liquid to a gas) within the encapsulatedphase change porous layer 300. According to such aspects, the flow ofthe cooling fluid (e.g., active heat management) and/or the nucleationof the cooling liquid (e.g., passive heat management) further enhancethe ability of the encapsulated phase change porous layer 300 todissipate heat from the heat generation device. More specifically, sucha flow of a cooling fluid and/or such a nucleation of a cooling liquidmay draw thermal energy being stored by the phase change material 304away from the phase change material 304 through the encapsulationmaterial. According to such aspects, the phase change material 304 isable to absorb further thermal energy (e.g., see FIG. 1B—via material112 of porous layer 103′, see FIG. 2B—via material 206 of porous layer103″) from a heat generating device coupled thereto.

Referring again to FIG. 3, according to various aspects, the phasechange material 304 may have a melting temperature substantially equalto a normal operating temperature of a heat generation device to whichthe encapsulated phase change porous layer 300 is to be coupled (seeFIG. 1A). According to other aspects, the phase change material 304 mayhave a melting temperature substantially equal to an expected operatingtemperature of the heat generation device. According to further aspects,the phase change material 304 may have a melting temperaturesubstantially equal to a predefined operating temperature of the heatgeneration device.

Further, referring to FIG. 3, according to various aspects, theencapsulation material 308 may have a melting temperature higher thanthat of the phase change material 304. According to other aspects, theencapsulation material 308 may have a melting temperature higher thanthat of the phase change material 304 and up to a maximum operatingtemperature of the heat generation device. According to further aspects,the encapsulation material 308 may have a melting temperature higherthan that of the phase change material 304 and equal to or higher thanthe maximum operating temperature of the heat generation device.According to such aspects, since the encapsulation material 308 has amelting temperature higher than the phase change material 304 and eitherup to, equal to or higher than the maximum operating temperature of theheat generation device, the encapsulation material 308 is able to retainthe phase change material 304 (e.g., in a melted, thermally storingphase) between the encapsulation material 308 and the metal surface 302of the encapsulated phase change porous layer 300.

In light of FIG. 3, according to various aspects described herein, whenthe heat generation device (e.g., semi-conductor chip and/or the like)operates at a temperature lower than the melting temperature associatedwith the phase change material 304 heat flux may be conducted from theheat generation device, through the metal 301 of the porous layer (e.g.,see FIG. 1B—through material 112 of porous layer 103′, see FIG.2B—through material 206 of porous layer 103″), through the phase changematerial 304, and through the encapsulation material 308. Notably, insuch an aspect, the phase change material 304 does not change phase.Further, in such an aspect, a cooling fluid (e.g., liquid and/or gas)flowing over the external surface 312 of the encapsulation material 308and/or a cooling liquid boiling off of the external surface 312 of theencapsulation material 308 may transfer heat away from the encapsulatedphase change porous layer 300 thereby effectively cooling a systemincluding the encapsulated phase change porous layer 300 and the heatgeneration device coupled thereto.

According to further aspects described herein, when the heat generationdevice (e.g., semi-conductor chip and/or the like) operates at atemperature higher than the melting temperature associated with thephase change material 304 heat flux may similarly be conducted from theheat generation device, through the metal 301 of the porous layer (e.g.,see FIG. 1B—through material 112 of porous layer 103′, see FIG.2B—through material 206 of porous layer 103″), through the phase changematerial 304, and through the encapsulation material 308 as described.However, in such an aspect, the phase change material 304 may absorbadditional thermal energy by changing phase from a solid to a liquidwhen its temperature increases above the melting temperature of thephase change material 304. Further, in such an aspect, a cooling fluid(e.g., liquid and/or gas) flowing over the external surface 312 of theencapsulation material 308 and/or a cooling liquid boiling off of theexternal surface 312 of the encapsulation material 308 may similarlytransfer heat away from the encapsulated phase change porous layer 300thereby effectively cooling a system including the encapsulated phasechange porous layer 300 and the heat generation device coupled thereto.Notably, in such an aspect, the phase change of the encapsulated phasechange material enables the encapsulated phase change porous layer 300to absorb more thermal energy relative to a porous layer not includingthe phase change material 304 and/or the encapsulation material 308.

Further, according to such an aspect, the cooling fluid flowing over theexternal surface 312 of the encapsulation material 308 and/or thecooling liquid boiling off of the external surface 312 of theencapsulation material 308 may effectively draw heat away from the phasechange material 304 such that the phase change material 304 is able toabsorb or draw further thermal energy from the heat generation device.Notably, in such aspects, since the melting temperature of theencapsulation material 308 is higher than the melting temperature of thephase change material 304 and either up to, equal to, or higher than themaximum operating temperature of the heat generation device, theencapsulation material 308 does not melt and the phase change material304 (e.g., in the liquid phase) is prevented from mixing with thecooling fluid and/or the cooling liquid.

Accordingly, in view of FIG. 3, since the phase change material 304 isunable to escape its position between the metal 301 of the porous layer(e.g., see FIG. 1B—material 112 of porous layer 103′, see FIG.2B—material 206 of porous layer 103″) and the encapsulation material308, the phase change material 304 may start to return from a liquidphase to a solid phase after a temperature of the heat generation devicedrops below the melting temperature of the phase change material 304.According to various aspects, such a configuration enables repeatedcycles of heating and cooling of the encapsulated phase change porouslayer 300 as needed or on demand to dissipate heat from the heatgeneration device.

FIG. 4 depicts a flow diagram 400 of an illustrative method of formingan encapsulated phase change porous layer (see FIG. 3, e.g.,encapsulated phase change porous layer 300) according to one or moreembodiments described herein. At block 402, the method may includedetermining one or more than one operating temperature associated with aheat generation device. According to aspects described herein, the heatgeneration device is to be thermally coupled to the encapsulated phasechange porous layer. According to some aspects, determining the one ormore than one operating temperature may include determining a normaloperating temperature. The normal operating temperature may becalculated based on standard operating conditions. According to otheraspects, determining the one or more than one operating temperature mayinclude determining an expected operating temperature. The expectedoperating temperature may be calculated based on anticipated operatingconditions. According to further aspects, determining the one or morethan one operating temperature may include determining a predefinedoperating temperature. The predefined operating temperature may be atemperature of the heat generation device at which the heat generationdevice efficiently performs its operations. According to yet furtheraspects, determining the one or more than one operating temperature mayinclude determining a maximum operating temperature. The maximumoperating temperature may be calculated based on a worst-case set ofoperating conditions. According to other aspects, the maximum operatingtemperature may be a temperature at which the heat generation device mayfail or has been tested to fail.

At block 404, the method may further include choosing a phase changematerial. According to some aspects described herein, choosing the phasechange material may include choosing a phase change material having amelting temperature equal to or higher than a normal operatingtemperature of the heat generation device (e.g., determined at block402). According to such aspects, choosing the phase change material mayinclude choosing a phase change material having a melting temperatureequal to or higher than the normal operating temperature of the heatgeneration device and less than the maximum operating temperature of theheat generation device. According to other aspects, choosing the phasechange material may include choosing a phase change material having amelting temperature equal to or higher than an expected operatingtemperature of the heat generation device (e.g., determined at block402). According to such aspects, choosing the phase change material mayinclude choosing a phase change material having a melting temperatureequal to or higher than the expected operating temperature of the heatgeneration device and less than the maximum operating temperature of theheat generation device. According to further aspects, choosing the phasechange material may include choosing a phase change material having amelting temperature equal to or higher than a predefined operatingtemperature of the heat generation device (e.g., determined at block402). According to such aspects, choosing the phase change material mayinclude choosing a phase change material having a melting temperatureequal to or higher than the predefined operating temperature of the heatgeneration device and less than the maximum operating temperature of theheat generation device.

At block 406, the method may further include choosing an encapsulationmaterial. According to some aspects described herein, choosing theencapsulation material may include choosing an encapsulation materialhaving a melting temperature higher than the melting temperatureassociated with the phase change material (e.g., chosen at block 404).According to other aspects, choosing the encapsulation material mayinclude choosing an encapsulation material having a melting temperaturehigher than the melting temperature associated with the phase changematerial (e.g., chosen at block 404) and up to the maximum operatingtemperature of the heat generation device. According to further aspects,choosing the encapsulation material may include choosing anencapsulation material having a melting temperature higher than themelting temperature associated with the phase change material (e.g.,chosen at block 404) and equal to or higher than the maximum operatingtemperature of the heat generation device.

At block 408, the method may further include providing or forming aporous layer. According to various aspects, the porous layer may bepre-existing (e.g., already formed). According to further aspectsdescribed herein, the porous layer may be formed via a sinteringprocess. According to alternative aspects, the porous layer may beformed via a process other than a sintering process (e.g., MIO, CIO,NIO, and/or the like).

At block 410, the method may further include forming (e.g., coating,layering or depositing) the phase change material (e.g., chosen at block404) over the structure or material (e.g., metal) of the porous layer(e.g., formed at block 408). According to various aspects, as discussedin FIG. 3 above, the phase change material over the structure ormaterial of the porous layer may include forming the phase changematerial to a first thickness or a predetermined thickness.

At block 412, the method may further include forming (e.g., coating,layering or depositing) the encapsulation material (e.g., chosen atblock 406) over the phase change material (e.g., chosen at block 404).According to various aspects, forming the encapsulation material overthe phase change material may include forming the encapsulation materialto encapsulate the phase change material between the encapsulationmaterial and the structure and/or material of the porous layer.According to further aspects, the encapsulation material may be formedover the phase change material to retain the phase change materialbetween the encapsulation material and the porous layer when a fluid(e.g., cooling fluid) is flowed through and/or in contact with theencapsulated phase change porous layer. According to various aspects, asdiscussed in FIG. 3 above, forming the encapsulation material over thephase change material may include forming the encapsulation material toa second thickness or a predetermined thickness.

At block 414, once the encapsulated phase change porous layer has beenformed (e.g., via block 402-412 described above). The method mayoptionally include (e.g., shown in phantom) coupling the formedencapsulated phase change porous layer to the heat generating device(e.g., associated with the operating temperatures determined at block402). According to various aspects, coupling the formed encapsulatedphase change porous layer to the heat generating device may includecoupling a cooling device, including the encapsulated phase changeporous layer, to the heat generating device (see FIG. 1A).

According to various alternative embodiments, more than one phase changematerial may be encapsulated within a provided or formed porous layer.For example, a first phase change material may be encapsulated in afirst portion of a porous layer (e.g., one side, one half, and/or thelike) and a second phase change material may be encapsulated in a secondportion of a porous layer (e.g., other side, other half, and/or thelike). According to yet further alternative embodiments, a phase changematerial may be encapsulated on only a portion of a porous layer (e.g.,one side, one half, and/or the like) and a remaining portion of theporous layer may not have a phase change material encapsulated thereon(e.g., other side, other half, and/or the like).

It should now be understood that the systems and methods describedherein are suitable for producing a porous layer exhibiting an enhancedheat capacity. More specifically, encapsulating a phase change materialbetween an encapsulation material and a metal of a porous layer (whereinthe phase change material and the encapsulation material have beenchosen based on operating temperatures associated with a heat generationdevice) produces an encapsulated phase change porous layer capable ofabsorbing increase thermal energy from the heat generation devicerelative to a porous layer not including a phase change material and/orencapsulation material.

While particular embodiments have been illustrated and described herein,it should be understood that various other changes and modifications maybe made without departing from the spirit and scope of the claimedsubject matter. Moreover, although various aspects of the claimedsubject matter have been described herein, such aspects need not beutilized in combination. It is therefore intended that the appendedclaims cover all such changes and modifications that are within thescope of the claimed subject matter.

What is claimed is:
 1. A heat transfer system, comprising: anencapsulated phase change porous layer, comprising: a porous layerdefined by a structure through which fluids are flowable; a phase changematerial formed over the structure of the porous layer, the phase changematerial comprising tin, indium, or paraffin wax; and an encapsulationmaterial formed over the phase change material such that theencapsulation material encapsulates the phase change material betweenthe encapsulation material and the structure of the porous layer andretains the phase change material between the encapsulation material andthe structure of the porous layer when a fluid is flowed through theporous layer.
 2. The heat transfer system of claim 1, wherein thestructure of the porous layer includes a network of pores that vary inat least one of size, shape, density, or distribution.
 3. The heattransfer system of claim 1, wherein the structure of the porous layerincludes a metal inverse opal structure having a plurality of dimplesand a plurality of pores.
 4. The heat transfer system of claim 3,wherein the plurality of pores permit the fluids to flow through theplurality of dimples.
 5. The heat transfer system of claim 3, whereineach of the plurality of dimples are spherical in shape.
 6. The heattransfer system of claim 1, wherein: the structure of the porous layeris defined by a porous layer material, the porous layer materialcomprising one of aluminum, nickel, copper, silver or gold; and theencapsulation material comprises one of copper or aluminum.
 7. The heattransfer system of claim 1, wherein the phase change material is formedover the structure of the porous layer to a first thickness.
 8. The heattransfer system of claim 7, wherein the encapsulation material is formedover the phase change material to a second thickness.
 9. A heat transfersystem, comprising: a heat generation device; and a cooling devicecoupled to the heat generation device, wherein the cooling devicecomprises an encapsulated phase change porous layer, comprising: aporous layer defined by a metal inverse opal (MIO) structure throughwhich fluids are flowable; a phase change material formed over the MIOstructure, the phase change material comprising tin, indium, or paraffinwax; and an encapsulation material formed over the phase change materialsuch that the encapsulation material encapsulates the phase changematerial between the encapsulation material and the MIO structure andretains the phase change material between the encapsulation material andthe MIO structure when a fluid is flowed through the porous layer. 10.The heat transfer system of claim 9, wherein the MIO structure comprisesa plurality of dimples and a plurality of pores.
 11. The heat transfersystem of claim 10, wherein the plurality of pores permit the fluids toflow through the plurality of dimples.
 12. The heat transfer system ofclaim 10, wherein each of the plurality of dimples are spherical inshape.
 13. The heat transfer system of claim 9, wherein: the MIOstructure is defined by a material comprising one of aluminum, nickel,copper, silver or gold; and the encapsulation material comprises one ofcopper or aluminum.
 14. The heat transfer system of claim 9, wherein thephase change material is formed over the MIO structure to a firstthickness.
 15. The heat transfer system of claim 14, wherein theencapsulation material is formed over the phase change material to asecond thickness.
 16. A method of forming an encapsulated phase changeporous layer, the method comprising: forming a porous layer that isdefined by a structure through which fluids are flowable; forming aphase change material over the structure of the porous layer, the phasechange material comprising tin, indium, or paraffin wax; and forming anencapsulation material over the phase change material such that theencapsulation material encapsulates the phase change material betweenthe encapsulation material and the structure of the porous layer andretains the phase change material between the encapsulation material andthe structure of the porous layer when a fluid is flowed through theporous layer.
 17. The method of claim 16, wherein the structure of theporous layer comprises a metal inverse opal (MIO) structure having aplurality of dimples and a plurality of pores formed via a MIO process.18. The method of claim 17, wherein: the MIO structure is defined by aporous layer material, the porous layer material comprising one ofaluminum, nickel, copper, silver or gold; and the encapsulation materialcomprises one of copper or aluminum.
 19. The method of claim 16, whereinforming the phase change material over the structure of the porous layercomprises layering, depositing or coating the phase change material overthe structure of the porous layer to a first thickness.
 20. The methodof claim 19, wherein forming the encapsulation material over the phasechange material comprises layering, depositing or coating theencapsulation material over the phase change material to a secondthickness.